▎ 摘　　要

Herein, a low-cost and eco-friendly approach is adopted for the synthesis of L-cysteine-assisted silver/reduced graphene oxide (L-cys-rGO/Ag) nanocomposites using sodium citrate as reducing agent. The morphology of graphene oxide (GO) and L-cys-rGO/Ag nanocomposites are studied by scanning electron microscope (SEM). The strong interactions of rGO/Ag with L-cysteine are established by Fourier transferred infrared (FTIR) study. The average diameter of dispersed Ag NPs is 40 to 70 nm, which is evidenced by transmission electron microscope (TEM). In the preparation of L-cys-rGO/Ag nanocomposites, both GO and L-cysteine are used as supporting and stabilising media to avoid the unexpected agglomeration in the in situ formed Ag NPs and to get high surface area in the nanocomposites. The excellent behaviour of L-cys-rGO/Ag nanocomposites acting as a heterogeneous catalyst for the conversion of 4-nitrophenol to 4-aminophenol with NaBH4 is achieved that is due to the high adsorption of reactant on the surface rGO and more transfers of electron from rGO to Ag NPs. Beside this, L-cys-rGO/Ag nanocatalyst can be reused several times with negligible loss of catalytic efficiency. Further, the as-synthesised nanocomposites show good antioxidant behaviour.